Apparatus for penetrating fog with a light beam



M. P. DEPUTY 3,426,139 APPARATUS FOR PENETRATING FOG WITH A LIGHT BEAM Feb. 4, 1969 Sheet Filed June 12, 1967 M Jr I Ill/4 Ill/ 41 1 Jew APPARATUS FOR PENETRA'IING FOG WITH A LIGHT BEAM Filed June 12, 1967 M. P DEPUTY 2 of L Sheet Fella 4, 1969 M. P. DEPUTY 3,426,189

APPARATUS FOR PENETRATING FOG WITH A LIGHT BEAM Filed June 12, 1967 Sheet 3 of4 M. P. DEPUTY 3,426,189

APPARATUS FOR PENETRATING FOG WITH A LIGHT BEAM Feb 4, 1969 Sheet PE/i/DLITUM WEUMA/tf, 5578a 45' WILL/4M5 Filed June 12, 1967 United States Patent 3,426,189 APPARATUS FOR PENETRATHNG FOG WlTH A LlGHT BEAM Marshall P. Deputy, 114 S. 1st St., Apt. 2, Council Bluffs, Iowa 51501 Continuation-impart of application Ser. No. 427,696, Jan. 25, 1965. This application lane 12, 1967, Ser. No. 655,256 U3. Ci. 24046.07 lint. Cl. lFZlv 11/04 11 Claims ABSTRACT @F THE DISCLOSURE Cross-references to related applications This is a continuation-in-part of my copending application Ser. No. 427,696, filed Jan. 25, 1965, now abandoned.

Background of the invention This invention relates generally to the field of illumination, and more particularly to fog penetrating lights for vehicles, such as automobiles and boats.

When a light beam is directed in fog, the fog scatters and diffuses the light and produces a milky curtain or glow zone that decreases the lighting contrasts by which objects are distinguished. As the intensity of the light beam is increased, the glow zone likewise increases and offsets any gain in visibility that might otherwise have been produced. Thus, when using ordinary light beams, visibility in fog is restricted to short distances. Various methods and devices have been proposed for overcoming these disadvantages and increasing visibility in fog, but none of these have provided a satisfactory answer to the problem.

One attempt to accomplish fog penetration has been to employ lamps with colored filters, amber being a preferred color; but these lamps have had limited intensity. The optimum intensity of an amber-colored lamp, for example, is only about 8800 candlepower; and at this intensity, the amber light will penetrate fog only up to a distance of approximately feet. It has been found that if the intensity of the amber lamp excteds 8800 candlepower, the degree of light scattering or light diffusion increases to a point where it creates excessive milkiness and actually reduces visibility. Because of the limitations on its fog-penetrating capabilities, the amber light or other filtered lamps do not afford adequate fog penetration for operation of highway vehicles, except at very low speeds; and they are totally ineffective for use on boats, which presently employ equipment such as radar, rather than fog lights.

Besides filtered lamps, intermittent lights have also been proposed for fog penetration, but the maximum intensity at which such lights may be operated is also severely limited. When a constant light is directed at fog, the light diflusion tends to be cumulative causing a rapid expansion of the glow zone. When a pulsating or intermittent light is employed, the intensity is periodically reduced so that the diffused light does not accumulate as quickly as with the constant light, and the excessive milkiness is not produced as rapidly. Thus, an intermittent light does achieve greater fog penetration than does a constant light; but, similar to the filtered light, as the intensity of the intermittent light is increased, the glow zone increases and restricts the fog-penetrating function of the light.

Accordingly, it is one object of this invention to provide apparatus which is capable of considerably greater penetration of fog with visibile light than the devices heretofore employed for this purpose. It is another object of this invention to provide fog-penetrating apparatus which produces higher intensity visible light beams than have been heretofore obtained. A further object is to provide fog-penetrating apparatus which produces a high intensity fog-penetrating light beam from a constant light source.

It is also an object of this invention to provide apparatus for penetrating fog in which a light beam is filtered and continuously oscillating between its maximum intensity and an essentially zero intensity.

It is also an obejct of this invention to provide apparatus for penetrating fog which produces a light beam that oscillates between a maximum intensity and an essentially zero intensity at a rate of speed which is fast enough to prevent flickering to the extent that it will cause eye fatigue and which is slow enough to prevent the build-up of a large glow zone and the consequent reduction of visibility.

It is also an object of this invention to provide a fog light which can be used on highway vehicles and boats.

It is also an object of this invention to provide a fog light which can be used for highway sign illumination and in similar applications.

It is also an object of this invention to provide a fog light which can be readily powered by the conventional electrical systems of highway vehicles and boats.

It is also an object of this invention to provide a fog light which can be economically and easily manufactured.

Further and additional objects will become manifest from the description, the drawings, and the appended claims.

Summary of the invention In one form of this invention, apparatus is provided comprising a light source; means for filtering the light emitted by the light source, preferably an amber-colored or blue-colored filter; a plurality of movable shutters secured together at their ends; and means for simultaneously actuating the shutters, such as an ordinary electric motor driving a cam connected to the shutters. The shutters, which may consist of bands or blades, are disposed intermediate the light source and the filtering means and interrupt at least a major proportion of the light emitted by the light source. The speed of the shutters is dependent upon the intensity of the light, the degree of penetration desired, and the density of the fog, a heavy fog requiring the greatest speed. When the shutters are operated at optimum speeds, the light beam produced by the device of this invention does not flicker excessively so as to cause consequent eye fatigue, and does not cause the buildup of an undesirable glow zone; and the device will produce improved visibility in fog.

When the device is to be used as a boat light, it will comprise an ordinary Searchlight as the light source, the movable shutters, and a colored filter capable of being moved into and out of the path of the light beam emitted by the light source. Because of the mobility of the filter, the boat light may function both as a searchlight and as a fog light. It is contemplated that the power source which drives the shutters will also energize a solenoid actuating the filter, so that when movement of the shutters is started, the solenoid will simultaneously actuate the filter into an While the optimum speed of the shutters will vary depending upon the degree of penetration desired and the fog conditions, it has been found that a shutter speed which causes between 12 to 42 flashes per second is preferred. In a boat light, where the light source is capable of producing light having an intensity of about 1,000,000 candlepower and the amount of light emitted through the filter will have an intensity of approximately 475,000 candlepower, the shutters should preferably be operated at a speed which will cause the light to flash from about 34 to 38 times per second.

FIG. 5 shows another embodiment 50 of this invention, which is especially adapted for use on highway vehicles. Similar to embodiment 10, this embodiment 50 also comprises a light source 52, movable shutters 54, and a filter 56. All of the foregoing elements are sealed in a housing 58 which keeps them relatively clean and protects them from moisture and weather conditions.

The light source 52 is a conventional sealed beam lamp, commonly used on automobiles, trucks, and other motor vehicles. The intensity of the sealed beam lamp will preferably vary between about 135,000 to 150,000 candlepower. The shutters 54 are preferably bands or blades which are horizontally disposed and parallel to each other. The shutters 54 are actuated in the same way that shutters 13 of embodiment are actuated, namely, by a cam 60 driven by a conventional electric motor. The motor, however, is not mounted within the housing 58, but is located remote from the unit 50. The filter 56, which is preferably amber-colored pot metal glass or blue glass, is fixed, rather than mobile as the filter 14 of embodiment 10. Thus, embodiment 50 functions primarily as a fog light; it does not perform the dual function of embodiment 10. Using sealed beam lamps producing light having the intensity mentioned above, and the aforementioned filters, about 75,000 candlepower of light will be emitted by the fog light 50.

The shutters 54 in unit 50 are mounted horizontally, rather than vertically, because this arrangement prevents the side reflection of light which occurs when the latter arrangement is used. In a highway vehicle, such side reflection is particularly undesirable. The shutters 54 are also mounted so that they close downward because this prevents upward reflected light, which is also undesirable in a highway vehicle since the drivers line of version is generally above the running lights of the vehicle.

Since most state highway laws require vehicles using the highways to employ lamps in pairs, it is contemplated that embodiment 50 will generally be used in banks of two with each light being aimed at substantially the same spot on the road in front of the vehicle. FIG. 6 is a schematic view showing an operating arrangement when two lights 50 are employed in a vehicle. The lights 50 are connected by cable 62 to a reduction gear box 64 which in turn is attached to an electric motor 66. The cable 62, which consists of an inner rotating member and an outer covering, is of the type normally used in automobile speedometers. It is connected to the end of the shaft 61 which is opposite that end thereof to which the cam 60 is attached. Cam 60 and shaft 61 are shown in FIG. 5, but the portion of the shaft 61 to which the cable 62 is attached is not shown. To achieve maximum fog penetration using a filtered lamp having approximately 75,000 candlepower, the light should flash at a frequency of about 23 to 26 times per second. Since two lights are normally used with highway vehicles, the shutters of each light will be operated at speeds which will produce approximately 11 /243 flashes per second, since the shutters of one light will be closed when the shutters of the other are open. The combined result of the two lights operating out of phase is equivalent to the optimum frequency of 23 to 26 flashes per second for a single light. Since a lower shutter speed will be used with the vehicle light,

a greater gear reduction ratio is used with the same size motor used to drive the shutters 13 of light 10.

An additional common state highway regulation prohibits total obstruction of vehicle lights. To comply with this regulation, the shutters 54 may be positioned so that when they are closed there are small spaces between them through which light having an intensity of up to about 50 candlepower may bleed. Another way in which to comply with this highway law is to mount within the housing 58, a small 25-candlepower lamp 59, which would always be unobstructed. Obviously, if the lamp 59 is employed, there is no need to provide the aforementioned spaces between the shutters.

FIG. 7 is a diagram of the electrical circuit of the embodiment 50 disclosed in FIG. 5. The circuit includes a power source 67, an on-off switch 68, the lamps 52 and S9 and the electric motor 66. When the switch 68 is moved to the on position, current flows from the power source and energizes the lamps and the motor.

FIG. 9 illustrates a third embodiment 70 of this invention. In this embodiment, a light source 72, such as a Searchlight, and a filter 74 are provided. Unit 70, also has shutters 76 which rotate through a 360 degree arc, and thus differ from the shutters 13 and 54 of units 10 and 50, respectively. Each shutter is connected to a corresponding spur gear 78 and each spur gear is meshed with the adjacent gears. Embodiment '70 is powered by an electric motor 79 which drives a spur gear 80 engaging the lowermost of the gears 78. The shutters open and close twice for each full rotation thereof, and thus produce two flashes for each complete rotation. The electrical circuit of embodiment 70 is similar to the one disclosed in FIG. 7 for embodiment 50, except that the ZS-candlepower lamp 59 is omitted.

In embodiment 70 each shutter 78 rotates in a direction opposite to the adjacent shutters, whereas in each of the embodiments 10 and 50, all of the shutters open and close in the same directions. Thus, the light beam produced by unit 70 is reflected both upwardly and downwardly, unlike the light beams of embodiments 10 and 50, which are not reflected upwardly. As noted hereinbefore, upward reflected light can interfere with the drivers ability to see the highway since his line of vision is located above the lights. On the other hand, a boat light is often mounted atop the pilot house, above the drivers line of vision, so that the matter of upward reflected light would not be important in such applications.

FIGS. 10 to 15 show another embodiment of this invention-an automotive fog lamp 100. This embodiment includes a housing 102, a sealed beam lamp 104 mounted therein, and a filter 106. Shutters 108, 110, 112, 114 and 116 are disposed between the lamp 104 and the filter 106. While five shutters are shown, more or less may be used where desired. Shutters 110, 112, and 114 are all the same length; shutters 108 and 116 are shorter.

The shutters are located in a housing 118 and are mounted in brackets 120 and 122, which are permanently fixed to the shutter housing 118 by means of screws or other means. Each shutter rotates about a central member 108a, 110a, 112a, 114a, and 116a (see, for example, FIGS. 12 and 15), the ends of the central members being inserted into holes provided in the brackets 120 and 122.

The shutters are actuated by a slide 124 that is connected to each shutter by means of pins 126 (see, particularly, FIGS. 12-15). The slide is moved up and down in the shutter housing by a crank 128, consisting of a pin 130 eccentrically mounted on a disc 132, and a shaft 134. The pin 130 extends through a slot 136 provided in the slide 124 (see FIG. 12). The shaft of the crank 128 extends through a bushing 138 and is threadably connected to the rotating member 139 of a cable 140 of the type normally used in automobile speedometers. The cable is driven by an electric motor which runs off the electrical system of the motor vehicle.

The slide 124 is provided with openings 142 through which the ends of the shutters are extended. The openings 142 are large enough to permit movement of the slide without interference from the shutters.

As the slide 124 is moved up and down, the shutters move downwardly between a horizontal position and a position which is about 80 degrees from the horizontal.

Thus, the fog lamp 100 will always emit at least a small quantity of light since the shutters must be substantially vertical to prevent entirely the emission of light. More over, because the shutters close downwardly, the light emitted by the fog lamp 100 will not be reflected upwardly into the drivers line of vision.

For each revolution of the crank 128 the slide will open and close the shutters once, thereby creating a single flash. Thus, to produce light flash 11% to 13 times per second, it will be necessary to rotate the crank at a speed of 11 /2 to 13 revolutions per second. A single motor operates both cranks of the two lights of a motor vehicle, and the cranks rotate at the same speed.

Using the fog lamp 100 in a motor vehicle, light fog may be penetrated as much as 300 feet whereas a dense fog may be penetrated a distance of 200 feet. This is in sharp contrast to the fog lamps of the prior art which can only penetrate light fog up to about 100 feet, and heavy fog up to about 25 feet.

Besides the specific embodiments and the modifications thereof hereinbefore described, it will be understood that additional modifications may be made that will come within the limits of this invention. For example, the light may be applicable to aircraft and other vehicles and craft than those described; the size, shape and number of the shutters may be varied; different types of light sources may be employed; other than amber-colored or blue glass may be used as a filter; and, where suitable, different means may be used to actuate the shutters and filter. Many further modifications will be apparent to those skilled in the art, and it is contemplated, therefore, by the appended claims to cover any such modifications as fall within the true spirit and scope of this invention.

What is claimed is:

1. Apparatus for penetrating fog with a beam of light comprising a light source; means for filtering the light emitted by said source; a plurality of horizontally disposed shutters positioned between the light source and the filtering means, said shutters being adapted to rotate downward from a parallel, open position to a substantially closed position so that a major proportion of said light is oscillated between a high intensity and a low intensity and said shutters being operated at a speed fast enough to prevent excessive flickering and slow enough to prevent the creation of an excessive glow zone; means for actuating said shutters so that all of the shutters open and close at essentially the same time.

2. The apparatus of claim 1 wherein the shutters rotate through an arc of approximately 80 degrees so that they are always at least slightly open.

3. The apparatus of claim 1 wherein the shutters open and close at speeds which produce light flashing at about 12 to 42 times per second.

4. The apparatus of claim 1, wherein the means for actuating said shutters includes a movable slide connected to said shutters, which slide moves the shutters between their open and closed positions; a cam connected to said slide, the rotation of said cam causing movement of said slide; and an electric motor for powering said cam.

5. The apparatus of claim 4, wherein a cable is attached to said electric motor and has a rotatable inner member which is actuated by the motor, said cable being connected to said cam and rotating therewith.

6. The apparatus of claim 5 wherein the light source is a sealed beam lamp; the intensity of the light emitted from apparatus is approximately 75,000 candlepower; and the cam comprises a rotatable crank having an eccentrically mounted pin inserted in a central slot in said slide, the rotation of said crank causing movement of said slide.

7. The apparatus of claim 6 wherein the crank rotates at a speed which causes the shutters to produce light flashing at approximately 23 to 26 times per second.

8. Apparatus for penetrating fog including at least two sources of light radiating in essentially the same directions, each of said light sources comprising a sealed beam lamp, meansf-or filtering the light emitted by said lamp; and a plurality of shutters disposed between the lamp and the filtering means, said shutters being adapted to rotate downward from a parallel, open position to a substantially closed position so that a major proportion of .said light is oscillated between a high intensity and a low intensity and said shutters being operated at a speed fast enough to prevent excessive flickering and slow enough to prevent the creation of an excessive glow zone; and means for actuating the shutters of each lamp so that the shutters of one lamp are open when the shutters of the other lamp are substantially closed.

9. The apparatus of claim 8 wherein the means for actuating the shutters is an electric motor, at least two cables each having a rotatable inner member actuated by said motor, and at least two rotating cams, each cam being connected to said shutters and to said cable inner member and rotating therewith.

10. Apparatus for penetrating fog with a beam of light, comprising a light source; means for filtering the light emitted by said source, said means being movable between operative and inoperative positions; at least one shutter interrupting a major proportion of the light emitted by the light source; means for actuating said shutter to oscillate at least a major proportion of the light between a high intensity and an essentially zero intensity at a speed fast enough to prevent excessive flickering and slow enough to prevent the creation of an excessive glow zone; means for effecting movement of the filtering means and synchronizing such movement with actuation of the shutters so that when the shutters are actuated, the filtering means is moved to its opeartive position, and when the shutters are stopped, the filtering means is moved to its inoperative position.

11. The apparatus of claim 10 wherein the means for actuating the shutters is an electric motor and the means for effecting movement of the filtering means is a solenoid switch.

References Cited UNITED STATES PATENTS 2,278,142 3/ 1942 Mack et a1. 2,423,322 7/ 1947 Hurley.

2,502,880 4/ 1950 Olinger 240--46.03 3,034,029 5/ 1962 Logan. 3,049,962 8/1962 Denecke. 3,333,094 7/1967 Steel 24046.11

NORTON ANSHER, Primary Examiner.

R. M. SHEER, Assistant Examiner.

US. Cl. X.R. 24046.59 

